Add a "fork" of musl as //fusl.

fusl/src/internal/libm.h

Index: fusl/src/internal/libm.h
diff --git a/fusl/src/internal/libm.h b/fusl/src/internal/libm.h
new file mode 100644
index 0000000000000000000000000000000000000000..df8641116af2ee442525828bfc27bc2de75ee508
--- /dev/null
+++ b/fusl/src/internal/libm.h
@@ -0,0 +1,184 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/math_private.h */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#ifndef _LIBM_H
+#define _LIBM_H
+
+#include <stdint.h>
+#include <float.h>
+#include <math.h>
+#include <complex.h>
+#include <endian.h>
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 && __BYTE_ORDER == __LITTLE_ENDIAN
+union ldshape {
+	long double f;
+	struct {
+		uint64_t m;
+		uint16_t se;
+	} i;
+};
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384 && __BYTE_ORDER == __LITTLE_ENDIAN
+union ldshape {
+	long double f;
+	struct {
+		uint64_t lo;
+		uint32_t mid;
+		uint16_t top;
+		uint16_t se;
+	} i;
+	struct {
+		uint64_t lo;
+		uint64_t hi;
+	} i2;
+};
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384 && __BYTE_ORDER == __BIG_ENDIAN
+union ldshape {
+	long double f;
+	struct {
+		uint16_t se;
+		uint16_t top;
+		uint32_t mid;
+		uint64_t lo;
+	} i;
+	struct {
+		uint64_t hi;
+		uint64_t lo;
+	} i2;
+};
+#else
+#error Unsupported long double representation
+#endif
+
+#define FORCE_EVAL(x) do {                        \
+	if (sizeof(x) == sizeof(float)) {         \
+		volatile float __x;               \
+		__x = (x);                        \
+	} else if (sizeof(x) == sizeof(double)) { \
+		volatile double __x;              \
+		__x = (x);                        \
+	} else {                                  \
+		volatile long double __x;         \
+		__x = (x);                        \
+	}                                         \
+} while(0)
+
+/* Get two 32 bit ints from a double.  */
+#define EXTRACT_WORDS(hi,lo,d)                    \
+do {                                              \
+  union {double f; uint64_t i;} __u;              \
+  __u.f = (d);                                    \
+  (hi) = __u.i >> 32;                             \
+  (lo) = (uint32_t)__u.i;                         \
+} while (0)
+
+/* Get the more significant 32 bit int from a double.  */
+#define GET_HIGH_WORD(hi,d)                       \
+do {                                              \
+  union {double f; uint64_t i;} __u;              \
+  __u.f = (d);                                    \
+  (hi) = __u.i >> 32;                             \
+} while (0)
+
+/* Get the less significant 32 bit int from a double.  */
+#define GET_LOW_WORD(lo,d)                        \
+do {                                              \
+  union {double f; uint64_t i;} __u;              \
+  __u.f = (d);                                    \
+  (lo) = (uint32_t)__u.i;                         \
+} while (0)
+
+/* Set a double from two 32 bit ints.  */
+#define INSERT_WORDS(d,hi,lo)                     \
+do {                                              \
+  union {double f; uint64_t i;} __u;              \
+  __u.i = ((uint64_t)(hi)<<32) | (uint32_t)(lo);  \
+  (d) = __u.f;                                    \
+} while (0)
+
+/* Set the more significant 32 bits of a double from an int.  */
+#define SET_HIGH_WORD(d,hi)                       \
+do {                                              \
+  union {double f; uint64_t i;} __u;              \
+  __u.f = (d);                                    \
+  __u.i &= 0xffffffff;                            \
+  __u.i |= (uint64_t)(hi) << 32;                  \
+  (d) = __u.f;                                    \
+} while (0)
+
+/* Set the less significant 32 bits of a double from an int.  */
+#define SET_LOW_WORD(d,lo)                        \
+do {                                              \
+  union {double f; uint64_t i;} __u;              \
+  __u.f = (d);                                    \
+  __u.i &= 0xffffffff00000000ull;                 \
+  __u.i |= (uint32_t)(lo);                        \
+  (d) = __u.f;                                    \
+} while (0)
+
+/* Get a 32 bit int from a float.  */
+#define GET_FLOAT_WORD(w,d)                       \
+do {                                              \
+  union {float f; uint32_t i;} __u;               \
+  __u.f = (d);                                    \
+  (w) = __u.i;                                    \
+} while (0)
+
+/* Set a float from a 32 bit int.  */
+#define SET_FLOAT_WORD(d,w)                       \
+do {                                              \
+  union {float f; uint32_t i;} __u;               \
+  __u.i = (w);                                    \
+  (d) = __u.f;                                    \
+} while (0)
+
+#undef __CMPLX
+#undef CMPLX
+#undef CMPLXF
+#undef CMPLXL
+
+#define __CMPLX(x, y, t) \
+	((union { _Complex t __z; t __xy[2]; }){.__xy = {(x),(y)}}.__z)
+
+#define CMPLX(x, y) __CMPLX(x, y, double)
+#define CMPLXF(x, y) __CMPLX(x, y, float)
+#define CMPLXL(x, y) __CMPLX(x, y, long double)
+
+/* fdlibm kernel functions */
+
+int    __rem_pio2_large(double*,double*,int,int,int);
+
+int    __rem_pio2(double,double*);
+double __sin(double,double,int);
+double __cos(double,double);
+double __tan(double,double,int);
+double __expo2(double);
+double complex __ldexp_cexp(double complex,int);
+
+int    __rem_pio2f(float,double*);
+float  __sindf(double);
+float  __cosdf(double);
+float  __tandf(double,int);
+float  __expo2f(float);
+float complex __ldexp_cexpf(float complex,int);
+
+int __rem_pio2l(long double, long double *);
+long double __sinl(long double, long double, int);
+long double __cosl(long double, long double);
+long double __tanl(long double, long double, int);
+
+/* polynomial evaluation */
+long double __polevll(long double, const long double *, int);
+long double __p1evll(long double, const long double *, int);
+
+#endif